Materials for organic electroluminescent devices

ABSTRACT

The present invention describes carbazolyl compounds substituted by electron-deficient heteroaryl groups, especially for use as triplet matrix materials in organic electroluminescent devices. The invention further relates to a process for preparing the compounds of the invention and to electronic devices comprising these.

The present invention describes carbazolyl compounds substituted byelectron-deficient heteroaryl groups, especially for use as tripletmatrix materials in organic electroluminescent devices. The inventionfurther relates to a process for preparing the compounds of theinvention and to electronic devices comprising these.

Emitting materials used in organic electroluminescent devices (OLEDs)are frequently organometallic complexes which exhibit phosphorescence.For quantum-mechanical reasons, up to four times the energy efficiencyand power efficiency is possible using organometallic compounds asphosphorescent emitters. In general terms, there is still a need forimprovement in OLEDs, especially also in OLEDs which exhibitphosphorescence, for example with regard to efficiency, operatingvoltage and lifetime.

The properties of phosphorescent OLEDs are not just determined by thetriplet emitters used. More particularly, the other materials used, forexample matrix materials, are also of particular significance here.Improvements to these materials can thus also lead to distinctimprovements in the OLED properties.

According to the prior art, matrix materials used for phosphorescentemitters in organic electroluminescent devices include carbazolederivatives and dibenzofuran derivatives. JP 2012-049518, U.S. Pat. Nos.7,935,434 and 8,221,908 disclose dibenzofuran derivatives substituted bytwo N-phenylcarbazolyl groups. WO 2014/081206 discloses compounds inwhich two carbazolyl groups, one of which is substituted on the nitrogenatom by an electron-deficient heteroaryl group, are joined to oneanother via an arylene group.

There is generally still a need for improvement in these materials foruse as matrix materials, in aspects including the external quantumefficiency (EQE). It is therefore an object of the present invention toprovide compounds suitable for use in a phosphorescent or fluorescentOLED, especially as matrix material. More particularly, it is an objectof the present invention to provide matrix materials which are suitablefor red-, yellow- and green-phosphorescing OLEDs and possibly also forblue-phosphorescing OLEDs, and which lead to long lifetime, goodefficiency and low operating voltage. More particularly, it is an objectof the present invention to provide materials that lead to an improvedexternal quantum efficiency.

It has been found that, surprisingly, electroluminescent devicescontaining compounds of the formula (1) below have improvements over theprior art, especially when used as matrix material for phosphorescentdopants.

The present invention therefore provides a compound of the followingformula (1):

where the symbols used are as follows:

-   A is the same or different at each instance and is CR or N, where    not more than two A groups per cycle are N, preferably not more than    one A group per cycle is N; more preferably, all A groups are CR;-   Y is O or S;-   W is the same or different at each instance and is CR or N, where    not more than two W groups per cycle are N and where W is C when an    L¹ or L² group is bonded to this position, or two adjacent W groups    together are a group of the following formula (2) or (3), where each    of the two carbazolyl derivative groups in the compound of the    formula (1) have not more than two groups of the formula (2) or    formula (3):

-   -   where the dotted bonds indicate the linkage of this group, A has        definitions given above and Z is NR, CR₂, O or S;

-   Ar¹, Ar² is an aromatic ring system having 5 to 30 aromatic ring    atoms or a dibenzofuran or dibenzothiophene group, where the    aromatic ring system or the dibenzofuran or dibenzothiophene group    may be substituted in each case by one or more nonaromatic R    radicals, or is a group of one of the following formulae (4) and    (5):

-   -   where the dotted bond represents the bond to the nitrogen atom;    -   with the proviso that exactly one of the Ar¹ and Ar² groups is a        group of one of the formulae (4) and (5);

-   X is the same or different at each instance and is CR or N, where X    in formula (5) is C when the group of the formula (5) in this    position is joined to L³, with the proviso that, in formula (4), two    or three X groups are N and, in formula (5), one, two or three X    groups are N;

-   L¹, L², L³ is the same or different at each instance and is a single    bond or an aromatic or heteroaromatic ring system which has 5 to 30    aromatic ring atoms and may be substituted by one or more R    radicals;

-   R is the same or different at each instance and is selected from the    group consisting of H, D, F, Cl, Br, I, CN, NO₂, N(R¹)₂, C(═O)R¹,    P(═O)(R¹)₂ P(R¹)₂, B(R¹)₂, Si(R¹)₃, a straight-chain alkyl, alkoxy    or thioalkyl group having 1 to 20 carbon atoms or a branched or    cyclic alkyl, alkoxy or thioalkyl group having 3 to 20 carbon atoms    or an alkenyl group having 2 to 20 carbon atoms, each of which may    be substituted by one or more R¹ radicals, where one or more    nonadjacent CH₂ groups may be replaced by R¹C═CR¹, Si(R¹)₂, C═O,    C═S, C═NR¹, P(═O)(R¹), SO, SO₂, NR¹, O, S or CONR¹ and where one or    more hydrogen atoms may be replaced by D, F, Cl, Br, I, CN or NO₂,    an aromatic or heteroaromatic ring system which has 5 to 40 aromatic    ring atoms and may be substituted in each case by one or more R¹    radicals, or an aryloxy or heteroaryloxy group which has 5 to 40    aromatic ring atoms and may be substituted by one or more R¹    radicals; at the same time, it is optionally possible for two R    substituents bonded to the same carbon atom or to adjacent carbon    atoms to form a monocyclic or polycyclic, aliphatic, aromatic or    heteroaromatic ring system which may be substituted by one or more    R¹ radicals;

-   R¹ is the same or different at each instance and is selected from    the group consisting of H, D, F, Cl, Br, I, CN, N(R²)₂, C(═O)R¹, a    straight-chain alkyl group having 1 to 10 carbon atoms or a branched    or cyclic alkyl group having 3 to 10 carbon atoms or an alkenyl    group having 2 to 10 carbon atoms, each of which may be substituted    by one or more R² radicals, where one or more hydrogen atoms may be    replaced by D, F, Cl, Br, I or CN, or an aromatic or heteroaromatic    ring system which has 5 to 40 aromatic ring atoms and may be    substituted in each case by one or more R² radicals; at the same    time, it is optionally possible for two R¹ substituents bonded to    the same carbon atom or to adjacent carbon atoms to form a    monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring    system which may be substituted by one or more R² radicals;

-   R² is the same or different at each instance and is selected from    the group consisting of H, D, F, CN, an aliphatic hydrocarbyl    radical having 1 to 20 carbon atoms, or an aromatic or    heteroaromatic ring system having 5 to 30 aromatic ring atoms in    which one or more hydrogen atoms may be replaced by D, F, CN and    which may be substituted by one or more alkyl groups each having 1    to 4 carbon atoms; at the same time, it is possible for two or more    adjacent R² substituents together to form a mono- or polycyclic,    aliphatic ring system.

Adjacent carbon atoms in the context of the present invention are carbonatoms bonded directly to one another.

The wording that two or more radicals together may form a ring, in thecontext of the present description, shall be understood to mean, interalia, that the two radicals are joined to one another by a chemical bondwith formal elimination of two hydrogen atoms. This is illustrated bythe following scheme:

In addition, however, the abovementioned wording shall also beunderstood to mean that, if one of the two radicals is hydrogen, thesecond radical binds to the position to which the hydrogen atom wasbonded, forming a ring. This shall be illustrated by the followingscheme:

An aryl group in the context of this invention contains 6 to 40 carbonatoms; a heteroaryl group in the context of this invention contains 2 to40 carbon atoms and at least one heteroatom, with the proviso that thesum total of carbon atoms and heteroatoms is at least 5. The heteroatomsare preferably selected from N, O and/or S, where the heteroaryl grouppreferably contains not more than three heteroatoms. An aryl group orheteroaryl group is understood here to mean either a simple aromaticcycle, i.e. benzene, or a simple heteroaromatic cycle, for examplepyridine, pyrimidine, thiophene, etc., or a fused aryl or heteroarylgroup, for example naphthalene, anthracene, phenanthrene, quinoline,isoquinoline, etc.

A fused aryl group in the context of the present invention is a group inwhich two or more aromatic groups are fused, i.e. annelated, to oneanother along a common edge, as, for example, in naphthalene. Bycontrast, for example, fluorene is not a fused aryl group in the contextof the present invention, since the two aromatic groups in fluorene donot have a common edge.

An aromatic ring system in the context of this invention contains 6 to40 carbon atoms in the ring system. A heteroaromatic ring system in thecontext of this invention contains 1 to 40 carbon atoms and at least oneheteroatom in the ring system, with the proviso that the sum total ofcarbon atoms and heteroatoms is at least 5. The heteroatoms arepreferably selected from N, O and/or S, where the heteroaromatic ringsystem preferably contains not more than four heteroatoms, morepreferably not more than three heteroatoms. An aromatic orheteroaromatic ring system in the context of this invention shall beunderstood to mean a system which does not necessarily contain only arylor heteroaryl groups, but in which it is also possible for two or morearyl or heteroaryl groups to be interrupted by a nonaromatic unit(preferably less than 10% of the atoms other than H), for example acarbon, nitrogen or oxygen atom or a carbonyl group. For example,systems such as 9,9′-spirobifluorene, 9,9-diarylfluorene, triarylamine,diaryl ethers, stilbene, etc. shall also be regarded as aromatic ringsystems in the context of this invention, and likewise systems in whichtwo or more aryl groups are interrupted, for example, by a linear orcyclic alkyl group. In addition, systems in which two or more aryl orheteroaryl groups are bonded directly to one another, for examplebiphenyl, terphenyl, quaterphenyl or bipyridine, shall likewise beregarded as an aromatic or heteroaromatic ring system.

A cyclic alkyl, alkoxy or thioalkoxy group in the context of thisinvention is understood to mean a monocyclic, bicyclic or polycyclicgroup.

In the context of the present invention, a C₁- to C₂₀-alkyl group inwhich individual hydrogen atoms or CH₂ groups may also be substituted bythe abovementioned groups are understood to mean, for example, themethyl, ethyl, n-propyl, i-propyl, cyclopropyl, n-butyl, i-butyl,s-butyl, t-butyl, cyclobutyl, 2-methylbutyl, n-pentyl, s-pentyl,t-pentyl, 2-pentyl, neopentyl, cyclopentyl, n-hexyl, s-hexyl, t-hexyl,2-hexyl, 3-hexyl, neohexyl, cyclohexyl, 1-methylcyclopentyl,2-methylpentyl, n-heptyl, 2-heptyl, 3-heptyl, 4-heptyl, cycloheptyl,1-methylcyclohexyl, n-octyl, 2-ethylhexyl, cyclooctyl,1-bicyclo[2.2.2]octyl, 2-bicyclo[2.2.2]octyl, 2-(2,6-dimethyl)octyl,3-(3,7-dimethyl)octyl, adamantyl, trifluoromethyl, pentafluoroethyl,2,2,2-trifluoroethyl, 1,1-dimethyl-n-hex-1-yl, 1,1-dimethyl-n-hept-1-yl,1,1-dimethyl-n-oct-1-yl, 1,1-dimethyl-n-dec-1-yl,1,1-dimethyl-n-dodec-1-yl, 1,1-dimethyl-n-tetradec-1-yl,1,1-dimethyl-n-hexadec-1-yl, 1,1-dimethyl-n-octadec-1-yl,1,1-diethyl-n-hex-1-yl, 1,1-diethyl-n-hept-1-yl, 1,1-diethyl-n-oct-1-yl,1,1-diethyl-n-dec-1-yl, 1,1-diethyl-n-dodec-1-yl,1,1-diethyl-n-tetradec-1-yl, 1,1-diethyl-n-hexadec-1-yl,1,1-diethyl-n-octadec-1-yl, 1-(n-propyl)cyclohex-1-yl,1-(n-butyl)cyclohex-1-yl, 1-(n-hexyl)cyclohex-1-yl,1-(n-octyl)cyclohex-1-yl and 1-(n-decyl)cyclohex-1-yl radicals. Analkenyl group is understood to mean, for example, ethenyl, propenyl,butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl,cycloheptenyl, octenyl, cyclooctenyl or cyclooctadienyl. An alkynylgroup is understood to mean, for example, ethynyl, propynyl, butynyl,pentynyl, hexynyl, heptynyl or octynyl. A C₁- to C₄₀-alkoxy group isunderstood to mean, for example, methoxy, trifluoromethoxy, ethoxy,n-propoxy, i-propoxy, n-butoxy, i-butoxy, s-butoxy, t-butoxy or2-methylbutoxy.

An aromatic or heteroaromatic ring system which has 5-40 aromatic ringatoms and may also be substituted in each case by the abovementionedradicals and which may be joined to the aromatic or heteroaromaticsystem via any desired positions is understood to mean, for example,groups derived from benzene, naphthalene, anthracene, benzanthracene,phenanthrene, benzophenanthrene, pyrene, chrysene, perylene,fluoranthene, benzofluoranthene, naphthacene, pentacene, benzopyrene,biphenyl, biphenylene, terphenyl, terphenylene, fluorene,spirobifluorene, dihydrophenanthrene, dihydropyrene, tetrahydropyrene,cis- or trans-indenofluorene, cis- or trans-monobenzoindenofluorene,cis- or trans-dibenzoindenofluorene, truxene, isotruxene, spirotruxene,spiroisotruxene, furan, benzofuran, isobenzofuran, dibenzofuran,thiophene, benzothiophene, isobenzothiophene, dibenzothiophene, pyrrole,indole, isoindole, carbazole, indolocarbazole, indenocarbazole,pyridine, quinoline, isoquinoline, acridine, phenanthridine,benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8-quinoline,phenothiazine, phenoxazine, pyrazole, indazole, imidazole,benzimidazole, naphthimidazole, phenanthrimidazole, pyridimidazole,pyrazinimidazole, quinoxalinimidazole, oxazole, benzoxazole,naphthoxazole, anthroxazole, phenanthroxazole, isoxazole, 1,2-thiazole,1,3-thiazole, benzothiazole, pyridazine, benzopyridazine, pyrimidine,benzopyrimidine, quinoxaline, 1,5-diazaanthracene, 2,7-diazapyrene,2,3-diazapyrene, 1,6-diazapyrene, 1,8-diazapyrene, 4,5-diazapyrene,4,5,9,10-tetraazaperylene, pyrazine, phenazine, phenoxazine,phenothiazine, fluorubine, naphthyridine, azacarbazole, benzocarboline,phenanthroline, 1,2,3-triazole, 1,2,4-triazole, benzotriazole,1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole,1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole,1,3,4-thiadiazole, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine,tetrazole, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine, 1,2,3,5-tetrazine,purine, pteridine, indolizine and benzothiadiazole.

Preference is given to the compounds of the following formula (1a):

where the symbols used have the definitions given above and A is C whenan L¹ or L² group is bonded to this position.

In a preferred embodiment of the invention, the L² group is a singlebond. A preferred embodiment of the compound of the formula (1) is thusa compound of the following formula (6), and a preferred embodiment ofthe compound of the formula (1a) is a compound of the formula (6a):

where the symbols used have the definitions given above.

In a preferred embodiment of the invention, W is the same or differentat each instance and is CR, or two W are a group of the formula (2a) or(3a) and the remaining W are CR, and A is the same or different at eachinstance and is CR. Preference is thus given to the compounds of thefollowing formulae (7a), (7b), (7c), (7d) and (7e):

where:

-   W two adjacent W groups together are a group of the following    formula (2a) or (3a) and the two other W groups are CR and    preferably CH, where W in formula (7d) is C when an L¹ group is    bonded to this position, and in formula (7e) is C when the    dibenzofuran or dibenzothiophene is bonded to this position:

-   -   where the dotted bonds indicate the linkage of this group;

-   n is the same or different at each instance and is 0, 1, 2, 3 or 4;

-   m is the same or different at each instance and is 0, 1, 2 or 3;

-   the further symbols used have the definitions given above.

In a further preferred embodiment of the invention, L¹ and L² are each asingle bond. Preference is thus given to the compounds of the followingformulae (8a), (8b), (8c), (8d) and (8e):

where the symbols and indices used have the definitions given above.

In a particularly preferred embodiment of the invention, the twocarbazole groups or carbazole derivatives are joined by the 3 position,i.e. via the position para to the nitrogen atoms. Particular preferenceis thus given to the compounds of the following formulae (9a), (9b),(9c), (9d) and (9e):

where the symbols and indices used have the definitions given above.

Very particular preference is given to compounds in which all W groupsare CR or C, i.e. the compounds of the formulae (7a), (8a) and (9a).

Preference is further given to compounds of the abovementioned formulaein which Y is O.

In a further preferred embodiment of the invention, Z, if the compoundcontains a group of the formula (2), is O, NR where the R radical bondedto the nitrogen is not H, or C(R)₂, more preferably NR where the Rradical bonded to the nitrogen is not H, or C(R)₂, and most preferablyC(R)₂.

In a preferred embodiment of the invention, each of the carbazolylderivative groups contains not more than one group of the formula (2) orformula (3).

When the compound of the invention contains a group of the formula (2),this may be bonded in various positions. This is shown hereinafter inschematic form with reference to preferred embodiments in which the Agroups and the other W groups are CR, by the formulae (A) to (F):

where the symbols and indices used have the definitions given above andthe dotted bond represents the linkage in the compound of the invention.The same applies to the other carbazole derivatives which, rather thanthe Ar¹ group, contains an Ar² group bonded to the nitrogen.

When the compound of the invention contains a group of the formula (3),this may be bonded in various positions. This is shown hereinafter inschematic form with reference to preferred embodiments in which the Agroups and the other W groups are CR, by the formulae (G) to (K):

where the symbols and indices used have the definitions given above andthe dotted bond represents the linkage in the compound of the invention.

The same applies to the other carbazole derivative containing an Ar²group.

There follows a description of preferred embodiments of the Ar¹ and Ar²groups. As described above, one of the Ar¹ and Ar² groups is an aromaticring system having 5 to 30 aromatic ring atoms or is a dibenzofuran ordibenzothiophene group, each of which may be substituted by one or morenonaromatic R radicals, and the other of the Ar¹ and Ar² groups is aheteroaryl group of one of the formulae (4) and (5).

In one embodiment of the compounds of formula (1) or (1a) or thecompounds of formula (6), (7a) to (7e), (8a) to (8e) and (9a) to (9e),Ar¹ is an aromatic ring system having 5 to 30 aromatic ring atoms or adibenzofuran or dibenzothiophene group, where the aromatic ring systemor the dibenzofuran or dibenzothiophene group may be substituted in eachcase by one or more nonaromatic R radicals, and Ar² is a heteroarylgroup of one of the formulae (4) and (5).

In a further embodiment of the compounds of formula (1) or (1a) or thecompounds of formula (6), (7a) to (7e), (8a) to (8e) and (9a) to (9e),Ar² is an aromatic ring system having 5 to 30 aromatic ring atoms or adibenzofuran or dibenzothiophene group, where the aromatic ring systemor the dibenzofuran or dibenzothiophene group may be substituted in eachcase by one or more nonaromatic R radicals, and Ar¹ is a heteroarylgroup of one of the formulae (4) and (5).

In a preferred embodiment of the invention, the group of the formula (4)is selected from the structures of the following formulae (4-1) to(4-3):

where the dotted bond represents the bond to the nitrogen atom and inaddition:

-   R is the same or different at each instance and is H, an alkyl group    which has 1 to 10 carbon atoms and may be substituted by one or more    R¹ radicals, but is preferably unsubstituted, or an aromatic or    heteroaromatic ring system which has 5 to 40 aromatic ring atoms and    may be substituted in each case by one or more R¹ radicals, but is    preferably unsubstituted; preferably, R is not H.

In a particularly preferred embodiment of the invention, the group ofthe formula (4) is selected from the structures of the followingformulae (4-1a) to (4-3a):

where the dotted bond represents the bond to the nitrogen atom and inaddition:

-   Ar is the same or different at each instance and is an aromatic or    heteroaromatic ring system which has 5 to 40 aromatic ring atoms and    may be substituted in each case by one or more R¹ radicals, but is    preferably unsubstituted.

In a preferred embodiment of the group of the formula (5), one or twosymbols X are N, more preferably two symbols X. Preferably, the group ofthe formula (5) is selected from the structures of the followingformulae (5-1) to (5-18):

where the dotted bond represents the bond to the nitrogen atom and inaddition:

-   R is the same or different at each instance and is H, an alkyl group    which has 1 to 10 carbon atoms and may be substituted by one or more    R¹ radicals, but is preferably unsubstituted, or an aromatic or    heteroaromatic ring system which has 5 to 40 aromatic ring atoms and    may be substituted in each case by one or more R¹ radicals, but is    preferably unsubstituted; preferably, R is not H.

More preferably, the group of the formula (5) is selected from thestructures of the following formulae (5-1a) to (5-18a):

where the dotted bond represents the bond to the nitrogen atom and Arhas the definitions given above.

In a preferred embodiment of the invention, L³ is the same or differentat each instance and is a single bond or an aromatic ring system having6 to 12 aromatic ring atoms, more preferably a single bond or para- ormeta-phenylene and most preferably a single bond.

In a further preferred embodiment of the invention, Ar in the groups ofthe formulae (4-1a) to (4-3a) and (5-1a) to (5-18a) is the same ordifferent at each instance and is an aromatic or heteroaromatic ringsystem having 6 to 24 aromatic ring atoms, preferably having 6 to 18aromatic ring atoms, more preferably an aromatic ring system having 6 to12 aromatic ring atoms or a heteroaromatic ring system having 6 to 13aromatic ring atoms, each of which may be substituted by one or more R¹radicals, but is preferably unsubstituted. Examples of suitable Argroups are selected from the group consisting of phenyl, ortho-, meta-or para-biphenyl, terphenyl, especially branched terphenyl,quaterphenyl, especially branched quaterphenyl, 1-, 2-, 3- or4-fluorenyl, 1-, 2-, 3- or 4-spirobifluorenyl, pyridyl, pyrimidinyl, 1-,2-, 3- or 4-dibenzofuranyl, 1-, 2-, 3- or 4-dibenzothienyl and 1-, 2-,3- or 4-carbazolyl, each of which may be substituted by one or more R¹radicals, but are preferably unsubstituted.

Examples of suitable Ar groups are the structures Ar-1 to Ar-19 groupslisted below:

where R¹ has the definitions given above and is preferably H, the dottedbond represents the linkage of this group and V is NR¹, O, S or C(R¹)₂.

In a further preferred embodiment of the invention, the Ar¹ or Ar² groupwhich is not a group of the formula (4) or (5) is an aromatic ringsystem having 6 to 24 aromatic ring atoms, preferably having 6 to 18aromatic ring atoms, more preferably having 6 to 12 aromatic ring atoms,or is a dibenzofuran or dibenzothiophene group, where these groups mayeach be substituted by one or more nonaromatic R radicals, but arepreferably unsubstituted. Examples of suitable Ar¹ or Ar² groups whichare not a group of the formula (4) or (5) are selected from the groupconsisting of phenyl, ortho-, meta- or para-biphenyl, terphenyl,especially branched terphenyl, quaterphenyl, especially branchedquaterphenyl, 1-, 2-, 3- or 4-fluorenyl, 1-, 2-, 3- or4-spirobifluorenyl, 1-, 2-, 3- or 4-dibenzofuranyl and 1-, 2-, 3- or4-dibenzothienyl, each of which may be substituted by one or morenonaromatic R radicals, but are preferably unsubstituted.

Examples of suitable Ar¹ or Ar² groups are the structures Ar¹-1 toAr¹-19 or Ar²-1 to Ar²-19 listed below:

where R has the definitions given above and is preferably H, the dottedbond represents the bond to the nitrogen atom and Y³ is the same ordifferent at each instance and is CR₂, O or S.

In a further preferred embodiment of the invention, in compounds of theformulae (7a) to (7e), (8a) to (8e) and (9a) to (9e), the index n is thesame or different at each instance and is 0, 1, 2 or 3, more preferably0, 1 or 2 and even more preferably 0 or 1 and especially 0.

In yet a further preferred embodiment of the invention, in compounds ofthe formulae (7a) to (7e), (8a) to (8e) and (9a) to (9e), the index m isthe same or different at each instance and is 0, 1 or 2, more preferably0 or 1 and even more preferably 0.

There follows a description of preferred substituents R. R is preferablyselected from the group consisting of H, D, F, CN, N(R¹)₂, C(═O)R¹,P(═O)(R¹)₂, a straight-chain alkyl or alkoxy group having 1 to 10 carbonatoms or a branched or cyclic alkyl or alkoxy group having 3 to 10carbon atoms or an alkenyl group having 2 to 10 carbon atoms, where thealkyl, alkoxy or alkenyl group may be substituted in each case by one ormore R¹ radicals, where one or more nonadjacent CH₂ groups may bereplaced by O and where one or more hydrogen atoms may be replaced by Dor F, an aromatic or heteroaromatic ring system which has 5 to 24aromatic ring atoms and may be substituted in each case by one or moreR¹ radicals, but is preferably unsubstituted; at the same time, it isoptionally possible for two R substituents bonded to the same carbonatom or to adjacent carbon atoms to form a monocyclic or polycyclic,aliphatic, aromatic or heteroaromatic ring system which may besubstituted by one or more R¹ radicals.

More preferably, these R substituents are selected from the groupconsisting of H, D, F, CN, a straight-chain alkyl group having 1 to 8carbon atoms, preferably having 1, 2, 3 or 4 carbon atoms, or a branchedor cyclic alkyl group having 3 to 8 carbon atoms, preferably having 3 or4 carbon atoms, or an alkenyl group having 2 to 8 carbon atoms,preferably having 2, 3 or 4 carbon atoms, where the alkyl or alkenylgroup may be substituted in each case by one or more R¹ radicals, but ispreferably unsubstituted, or an aromatic or heteroaromatic ring systemhaving 6 to 24 aromatic ring atoms, preferably having 6 to 18 aromaticring atoms, more preferably having 6 to 13 aromatic ring atoms, each ofwhich may be substituted by one or more nonaromatic R¹ radicals, but ispreferably unsubstituted; at the same time, it is optionally possiblefor two R substituents bonded to the same carbon atom or to adjacentcarbon atoms to form a monocyclic or polycyclic aliphatic ring systemwhich may be substituted by one or more R¹ radicals, but is preferablyunsubstituted.

Most preferably, the R substituents are selected from the groupconsisting of H and an aromatic or heteroaromatic ring system having 6to 18 aromatic ring atoms, preferably having 6 to 13 aromatic ringatoms, each of which may be substituted by one or more nonaromatic R¹radicals, but is preferably unsubstituted. Examples of suitable Rsubstituents are selected from the group consisting of phenyl, ortho-,meta- or para-biphenyl, terphenyl, especially branched terphenyl,quaterphenyl, especially branched quaterphenyl, 1-, 2-, 3- or4-fluorenyl, 1-, 2-, 3- or 4-spirobifluorenyl, pyridyl, pyrimidinyl, 1-,2-, 3- or 4-dibenzofuranyl, 1-, 2-, 3- or 4-dibenzothienyl and 1-, 2-,3- or 4-carbazolyl, each of which may be substituted by one or more R¹radicals, but are preferably unsubstituted. Suitable structures R arethe same structures as depicted above for Ar-1 to Ar-19.

When Z in the structure of the formula (2) is NR, it is preferable whenthe R radical bonded to this nitrogen atom is the same or different ateach instance and is an aromatic or heteroaromatic ring system which has5 to 24 aromatic ring atoms and may be substituted in each case by oneor more R¹ radicals, more preferably an aromatic or heteroaromatic ringsystem which has 6 to 18 aromatic ring atoms and may be substituted byone or more R¹ radicals. Examples of suitable R substituents areselected from the group consisting of phenyl, ortho-, meta- orpara-biphenyl, terphenyl, especially branched terphenyl, quaterphenyl,especially branched quaterphenyl, 1-, 2-, 3- or 4-fluorenyl, 1-, 2-, 3-or 4-spirobifluorenyl, pyridyl, pyrimidinyl, 1,3,5-triazinyl,4,6-diphenyl-1,3,5-triazinyl, 1-, 2-, 3- or 4-dibenzofuranyl, 1-, 2-, 3-or 4-dibenzothienyl and 1-, 2-, 3- or 4-carbazolyl, where the carbazolylgroup is substituted on the nitrogen atom by an R¹ radical other than Hor D. These groups may each be substituted by one or more R¹ radicals,but are preferably unsubstituted. Suitable structures R are the samestructures as depicted above for Ar-1 to Ar-19.

In a further preferred embodiment of the invention, R¹ is the same ordifferent at each instance and is selected from the group consisting ofH, D, F, CN, an aliphatic hydrocarbyl radical having 1 to 6 carbonatoms, preferably having 1, 2, 3 or 4 carbon atoms, or an aromatic orheteroaromatic ring system having 5 to 30 aromatic ring atoms,preferably having 5 to 24 aromatic ring atoms, more preferably having 5to 13 aromatic ring atoms, which may be substituted by one or more alkylgroups each having 1 to 4 carbon atoms, but is preferably unsubstituted.

It is further preferable when the aromatic or heteroaromatic R or R¹ orR² or Ar¹ or Ar² groups in the compound of the invention do not have anyaryl or heteroaryl groups having more than two aromatic six-memberedrings fused directly to one another. Fused aryl groups which have morethan two aromatic six-membered rings are fused directly to one anotherbut are nevertheless also suitable in accordance with the invention arephenanthrene and triphenylene, since these also have a high tripletlevel.

The abovementioned preferences can occur individually or together. It ispreferable when the abovementioned preferences occur together.

Very particular preference is given to the compounds of the followingformulae (10) and (11):

where the symbols used have the definitions given above and especiallythe preferred definitions given above.

Examples of suitable compounds of the invention are the structuresdepicted below:

The compounds of the invention can be prepared by synthesis steps knownto those skilled in the art, for example bromination, Suzuki coupling,Ullmann coupling, Hartwig-Buchwald coupling, etc. A suitable synthesismethod is shown in general terms in Scheme 2 below: Scheme 1 shows thesynthesis of the 1-bromo-substituted dibenzofuran which is used asreactant. Scheme 2 shows the functionalization of the dibenzofuran inthe 8 position and the conversion to the compounds of the invention.

The present invention therefore further provides a process for preparingthe compounds of the invention by reacting an optionally substituted1,8-dihalodibenzofuran or 1,8-dihalodibenzothiophene or a correspondingderivative having one or more nitrogen atoms in the base skeleton with acarbazole derivative, followed by reaction with the other carbazolederivative, where the reactions with the carbazole derivatives are eachC—C couplings, especially Suzuki couplings.

For the processing of the compounds of the invention from a liquidphase, for example by spin-coating or by printing methods, formulationsof the compounds of the invention are required. These formulations may,for example, be solutions, dispersions or emulsions. For this purpose,it may be preferable to use mixtures of two or more solvents. Suitableand preferred solvents are, for example, toluene, anisole, o-, m- orp-xylene, methyl benzoate, mesitylene, tetralin, veratrole, THF,methyl-THF, THP, chlorobenzene, dioxane, phenoxytoluene, especially3-phenoxytoluene, (−)-fenchone, 1,2,3,5-tetramethylbenzene,1,2,4,5-tetramethylbenzene, 1-methylnaphthalene, 2-methylbenzothiazole,2-phenoxyethanol, 2-pyrrolidinone, 3-methylanisole, 4-methylanisole,3,4-dimethylanisole, 3,5-dimethylanisole, acetophenone, α-terpineol,benzothiazole, butyl benzoate, cumene, cyclohexanol, cyclohexanone,cyclohexylbenzene, decalin, dodecylbenzene, ethyl benzoate, indane,methyl benzoate, NMP, p-cymene, phenetole, 1,4-diisopropylbenzene,dibenzyl ether, diethylene glycol butyl methyl ether, triethylene glycolbutyl methyl ether, diethylene glycol dibutyl ether, triethylene glycoldimethyl ether, diethylene glycol monobutyl ether, tripropylene glycoldimethyl ether, tetraethylene glycol dimethyl ether,2-isopropylnaphthalene, pentylbenzene, hexylbenzene, heptylbenzene,octylbenzene, 1,1-bis(3,4-dimethylphenyl)ethane, hexamethylindane ormixtures of these solvents.

The present invention therefore further provides a formulationcomprising a compound of the invention and at least one furthercompound. The further compound may, for example, be a solvent,especially one of the abovementioned solvents or a mixture of thesesolvents. The further compound may alternatively be at least one furtherorganic or inorganic compound which is likewise used in the electronicdevice, for example an emitting compound, especially a phosphorescentdopant, and/or a further matrix material. Suitable emitting compoundsand further matrix materials are listed at the back in connection withthe organic electroluminescent device. This further compound may also bepolymeric.

The compounds of the invention and mixtures are suitable for use in anelectronic device. An electronic device is understood to mean a devicecontaining at least one layer containing at least one organic compound.This component may also comprise inorganic materials or else layersformed entirely from inorganic materials.

The present invention therefore further provides for the use of thecompounds or mixtures of the invention in an electronic device,especially in an organic electroluminescent device.

The present invention still further provides an electronic devicecomprising at least one of the above-detailed compounds or mixtures ofthe invention.

In this case, the preferences detailed above for the compound also applyto the electronic devices.

The electronic device is preferably selected from the group consistingof organic electroluminescent devices (OLEDs, PLEDs), organic integratedcircuits (O-ICs), organic field-effect transistors (O-FETs), organicthin-film transistors (O-TFTs), organic light-emitting transistors(O-LETs), organic solar cells (O-SCs), organic dye-sensitized solarcells, organic optical detectors, organic photoreceptors, organicfield-quench devices (O-FQDs), light-emitting electrochemical cells(LECs), organic laser diodes (O-lasers) andorganic plasmon emittingdevices (D. M. Koller et al., Nature Photonics 2008, 1-4), preferablyorganic electroluminescent devices (OLEDs, PLEDs), especiallyphosphorescent OLEDs.

The organic electroluminescent device comprises cathode, anode and atleast one emitting layer. Apart from these layers, it may also comprisefurther layers, for example in each case one or more hole injectionlayers, hole transport layers, hole blocker layers, electron transportlayers, electron injection layers, exciton blocker layers, electronblocker layers and/or charge generation layers. It is likewise possiblefor interlayers having an exciton-blocking function, for example, to beintroduced between two emitting layers. However, it should be pointedout that not necessarily every one of these layers need be present. Inthis case, it is possible for the organic electroluminescent device tocontain an emitting layer, or for it to contain a plurality of emittinglayers. If a plurality of emission layers are present, these preferablyhave several emission maxima between 380 nm and 750 nm overall, suchthat the overall result is white emission; in other words, variousemitting compounds which may fluoresce or phosphoresce are used in theemitting layers. Especially preferred are systems having three emittinglayers, where the three layers show blue, green and orange or redemission (for the basic construction, see, for example, WO 2005/011013).These may be fluorescent or phosphorescent emission layers or elsehybrid systems in which fluorescent and phosphorescent emission layersare combined with one another. A white-emitting electroluminescentdevice can be used, for example, for lighting applications, but also incombination with a colour filter for full-colour displays.

The compound of the invention according to the above-detailedembodiments may be used in different layers, according to the exactstructure. Preference is given to an organic electroluminescent devicecontaining a compound of formula (1) or according to the preferredembodiments as matrix material for fluorescent or phosphorescentemitters, especially for phosphorescent emitters, and/or as electrontransport or hole blocker material in an electron transport layer and/orin a hole-blocking layer, according to the exact substitution. In thiscontext, the above-detailed preferred embodiments also apply to the useof the materials in organic electronic devices.

In a preferred embodiment of the invention, the compound of formula (1)or according to the preferred embodiments is used as matrix material fora phosphorescent compound in an emitting layer. In this case, theorganic electroluminescent device may contain an emitting layer, or itmay contain a plurality of emitting layers, where at least one emittinglayer contains at least one compound of the invention as matrixmaterial.

When the compound of formula (1) or according to the preferredembodiments is used as matrix material for an emitting compound in anemitting layer, it is preferably used in combination with one or morephosphorescent materials (triplet emitters). Phosphorescence in thecontext of this invention is understood to mean luminescence from anexcited state having spin multiplicity >1, especially from an excitedtriplet state. In the context of this application, all luminescenttransition metal complexes and luminescent lanthanide complexes,especially all iridium, platinum and copper complexes, shall be regardedas phosphorescent compounds.

The mixture of the compound of formula (1) or according to the preferredembodiments and the emitting compound contains between 99% and 1% byvolume, preferably between 98% and 10% by volume, more preferablybetween 97% and 60% by volume and especially between 95% and 80% byvolume of the compound of formula (1) or according to the preferredembodiments, based on the overall mixture of emitter and matrixmaterial. Correspondingly, the mixture contains between 1% and 99% byvolume, preferably between 2% and 90% by volume, more preferably between3% and 40% by volume and especially between 5% and 20% by volume of theemitter, based on the overall mixture of emitter and matrix material. Ifthe compounds are processed from solution, preference is given to usingthe corresponding amounts in % by weight rather than the above-specifiedamounts in % by volume.

Suitable phosphorescent compounds (=triplet emitters) are especiallycompounds which, when suitably excited, emit light, preferably in thevisible region, and also contain at least one atom of atomic numbergreater than 20, preferably greater than 38 and less than 84, morepreferably greater than 56 and less than 80, especially a metal havingthis atomic number. Preferred phosphorescence emitters used arecompounds containing copper, molybdenum, tungsten, rhenium, ruthenium,osmium, rhodium, iridium, palladium, platinum, silver, gold or europium,especially compounds containing iridium or platinum. In the context ofthe present invention, all luminescent compounds containing theabovementioned metals are regarded as phosphorescent compounds.

Examples of the above-described emitters can be found in applications WO00/70655, WO 2001/41512, WO 2002/02714, WO 2002/15645, EP 1191613, EP1191612, EP 1191614, WO 05/033244, WO 05/019373, US 2005/0258742, WO2009/146770, WO 2010/015307, WO 2010/031485, WO 2010/054731, WO2010/054728, WO 2010/086089, WO 2010/099852, WO 2010/102709, WO2011/032626, WO 2011/066898, WO 2011/157339, WO 2012/007086, WO2014/008982, WO 2014/023377, WO 2014/094961, WO 2014/094960, WO2015/036074, WO 2015/104045, WO 2015/117718, WO 2016/015815 and the asyet unpublished applications EP 15000307.7, EP 15182264.0 and EP16179378.1. In general, all phosphorescent complexes as used forphosphorescent OLEDs according to the prior art and as known to thoseskilled in the art in the field of organic electroluminescence aresuitable, and the person skilled in the art will be able to use furtherphosphorescent complexes without exercising inventive skill.

A further preferred embodiment of the present invention is the use ofthe compound of formula (1) or according to the preferred embodiments asmatrix material for a phosphorescent emitter in combination with afurther matrix material. In a preferred embodiment of the invention, thefurther matrix material is a hole-transporting compound. In a furtherpreferred embodiment of the invention, the further matrix material is anelectron-transporting compound. In yet a further preferred embodiment,the further matrix material is a compound having a large band gap whichis not involved to a significant degree, if at all, in the hole andelectron transport in the layer.

Suitable matrix materials for the compounds of the invention areketones, phosphine oxides, sulphoxides and sulphones, for exampleaccording to WO 2004/013080, WO 2004/093207, WO 2006/005627 or WO2010/006680, triarylamines, carbazole derivatives, e.g. CBP(N,N-biscarbazolylbiphenyl), m-CBP or the carbazole derivativesdisclosed in WO 2005/039246, US 2005/0069729, JP 2004/288381, EP1205527, WO 2008/086851 or US 2009/0134784, combinations of triazinesand carbazoles, for example according to WO 2011/057706 or WO2014/015931, indolocarbazole derivatives, for example according to WO2007/063754 or WO 2008/056746, indenocarbazole derivatives, for exampleaccording to WO 2010/136109, WO 2011/000455, WO 2013/041176 or WO2013/056776, spiroindenocarbazole derivatives, for example according toWO 2014/094963 or WO 2015/124255, azacarbazoles, for example accordingto EP 1617710, EP 1617711, EP 1731584, JP 2005/347160, bipolar matrixmaterials, for example according to WO 2007/137725, lactams, for exampleaccording to WO 2011/116865, WO 2011/137951, WO 2013/064206 or WO2014/056567, silanes, for example according to WO 2005/111172,azaboroles or boronic esters, for example according to WO 2006/117052 orWO 2013/091762, diazasilole derivatives, for example according to WO2010/054729, diazaphosphole derivatives, for example according to WO2010/054730, triazine derivatives, for example according to WO2010/015306, WO 2007/063754, WO 2008/056746 or WO 2014/023388, zinccomplexes, for example according to EP 652273 or WO 2009/062578,dibenzofuran derivatives, for example according to WO 2009/148015, WO2015/169412, WO 2016/015810 or WO 2016/023608, bridged carbazolederivatives, for example according to US 2009/0136779, WO 2010/050778,WO 2011/042107 or WO 2011/088877, or triphenylene derivatives, forexample according to WO 2012/048781. It is likewise possible for afurther phosphorescent emitter which emits at a shorter wavelength thanthe actual emitter to be present as co-host in the mixture.

Preferred co-host materials are triarylamine derivatives, especiallymonoamines, indenocarbazole derivatives, 4-spirocarbazole derivatives,lactams, triazine derivatives and carbazole derivatives.

Preferred triarylamine derivatives which are used as co-host materialstogether with the compounds of the invention are selected from thecompounds of the following formula (12):

where Ar is the same or different at each instance and has thedefinitions given above. Preferably, the Ar groups are the same ordifferent at each instance and are selected from the abovementioned Ar-1to Ar-19 groups.

In a preferred embodiment of the compounds of the formula (12), at leastone Ar group is selected from a biphenyl group, which may be an ortho-,meta- or para-biphenyl group. In a further preferred embodiment of thecompounds of the formula (12), at least one Ar group is selected from afluorene group or spirobifluorene group, where these groups may each bebonded to the nitrogen atom in the 1, 2, 3 or 4 position. In yet afurther preferred embodiment of the compounds of the formula (12), atleast one Ar group is selected from a phenylene or biphenyl group, wherethe group is an ortho-, meta- or para-bonded group, substituted by adibenzofuran group, a dibenzothiophene group or a carbazole group,especially a dibenzofuran group, where the dibenzofuran ordibenzothiophene group is bonded to the phenylene or biphenyl group viathe 1, 2, 3 or 4 position and where the carbazole group is bonded to thephenylene or biphenyl group via the 1, 2, 3 or 4 position or via thenitrogen atom.

In a particularly preferred embodiment of the compounds of the formula(12), one Ar group is selected from a fluorene or spirobifluorene group,especially a 4-fluorene or 4-spirobifluorene group, and one Ar group isselected from a biphenyl group, especially a para-biphenyl group, or afluorene group, especially a 2-fluorene group, and the third Ar group isselected from a para-phenylene group or a para-biphenyl group,substituted by a dibenzofuran group, especially a 4-dibenzofuran group,or a carbazole group, especially an N-carbazole group or a 3-carbazolegroup.

Preferred indenocarbazole derivatives which are used as co-hostmaterials together with the compounds of the invention are selected fromthe compounds of the following formula (13):

where Ar and R have the definitions listed above. Preferred embodimentsof the Ar group are the structures Ar-1 to Ar-19 listed above.

A preferred embodiment of the compounds of the formula (13) is thecompounds of the following formula (13a):

where Ar and R have the definitions given above. The two R groups bondedto the indeno carbon atom here are preferably the same or different andare each an alkyl group having 1 to 4 carbon atoms, especially methylgroups, or an aromatic ring system having 6 to 12 carbon atoms,especially phenyl groups. More preferably, the two R groups are bondedto the indeno carbon atom are methyl groups. Further preferably, the Rsubstituent bonded to the indenocarbazole base skeleton in formula (13a)is H or a carbazole group which may be bonded to the indenocarbazolebase skeleton via the 1, 2, 3 or 4 position or via the nitrogen atom,especially via the 3 position.

Preferred 4-spirocarbazole derivatives which are used as co-hostmaterials together with the compounds of the invention are selected fromthe compounds of the following formula (14):

where Ar and R have the definitions listed above. Preferred embodimentsof the Ar group are the structures Ar-1 to Ar-19 listed above.

A preferred embodiment of the compounds of the formula (14) is thecompounds of the following formula (14a):

where Ar and R have the definitions given above.

Preferred lactams which are used as co-host materials together with thecompounds of the invention are selected from the compounds of thefollowing formula (15):

where R has the definitions listed above.

A preferred embodiment of the compounds of the formula (15) is thecompounds of the following formula (15a):

where R has the definitions given above. Preferably, R here is the sameor different at each instance and is H or an aromatic or heteroaromaticring system which has 5 to 40 aromatic ring atoms and which may besubstituted by one or more R¹ radicals. Most preferably, the Rsubstituents are selected from the group consisting of H and an aromaticor heteroaromatic ring system having 6 to 18 aromatic ring atoms,preferably having 6 to 13 aromatic ring atoms, each of which may besubstituted by one or more nonaromatic R¹ radicals, but is preferablyunsubstituted. Examples of suitable R substituents are selected from thegroup consisting of phenyl, ortho-, meta- or para-biphenyl, terphenyl,especially branched terphenyl, quaterphenyl, especially branchedquaterphenyl, 1-, 2-, 3- or 4-fluorenyl, 1-, 2-, 3- or4-spirobifluorenyl, pyridyl, pyrimidinyl, 1-, 2-, 3- or4-dibenzofuranyl, 1-, 2-, 3- or 4-dibenzothienyl and 1-, 2-, 3- or4-carbazolyl, each of which may be substituted by one or more R¹radicals, but are preferably unsubstituted. Suitable structures R arethe same structures as depicted above for Ar-1 to Ar-19, where thesestructures are substituted by R¹ rather than R.

In a further embodiment of the invention, the organic electroluminescentdevice of the invention does not contain any separate hole injectionlayer and/or hole transport layer and/or hole blocker layer and/orelectron transport layer, meaning that the emitting layer directlyadjoins the hole injection layer or the anode, and/or the emitting layerdirectly adjoins the electron transport layer or the electron injectionlayer or the cathode, as described, for example, in WO 2005/053051. Itis additionally possible to use a metal complex identical or similar tothe metal complex in the emitting layer as hole transport or holeinjection material directly adjoining the emitting layer, as described,for example, in WO 2009/030981.

In addition, it is possible to use the compounds of the invention in ahole blocker or electron transport layer.

In the further layers of the organic electroluminescent device of theinvention, it is possible to use any materials as typically usedaccording to the prior art. The person skilled in the art is thereforeable, without exercising inventive skill, to use any materials known fororganic electroluminescent devices in combination with the inventivecompounds of formula (1) or according to the preferred embodiments.

Additionally preferred is an organic electroluminescent device,characterized in that one or more layers are coated by a sublimationprocess. In this case, the materials are applied by vapour deposition invacuum sublimation systems at an initial pressure of less than 10⁻⁵mbar, preferably less than 10⁻⁶ mbar. It is also possible that theinitial pressure is even lower or higher, for example less than 10⁻⁷mbar.

Preference is likewise given to an organic electroluminescent device,characterized in that one or more layers are coated by the OVPD (organicvapour phase deposition) method or with the aid of a carrier gassublimation. In this case, the materials are applied at a pressurebetween 10⁻⁵ mbar and 1 bar. A special case of this method is the OVJP(organic vapour jet printing) method, in which the materials are applieddirectly by a nozzle and thus structured (for example, M. S. Arnold etal., Appl. Phys. Lett. 2008, 92, 053301).

Preference is additionally given to an organic electroluminescentdevice, characterized in that one or more layers are produced fromsolution, for example by spin-coating, or by any printing method, forexample inkjet printing, LITI (light-induced thermal imaging, thermaltransfer printing), screen printing, flexographic printing, offsetprinting or nozzle printing. For this purpose, soluble compounds areneeded, which are obtained, for example, through suitable substitution.

In addition, hybrid methods are possible, in which, for example, one ormore layers are applied from solution and one or more further layers areapplied by vapour deposition. For example, it is possible to apply theemitting layer from solution and to apply the electron transport layerby vapour deposition.

These methods are known in general terms to those skilled in the art andcan be applied by those skilled in the art without exercising inventiveskill to organic electroluminescent devices comprising the compounds ofthe invention.

The compounds of the invention generally have very good properties onuse in organic electroluminescent devices. Especially in the case of useof the compounds of the invention in organic electroluminescent devices,the lifetime is significantly better compared to similar compoundsaccording to the prior art. At the same time, the further properties ofthe organic electroluminescent device, especially the efficiency andvoltage, are likewise better or at least comparable.

The invention is now illustrated in detail by the examples which follow,without any intention of restricting it thereby.

EXAMPLES

The syntheses which follow, unless stated otherwise, are conducted undera protective gas atmosphere in dried solvents. The solvents and reagentscan be purchased, for example, from Sigma-ALDRICH or ABCR. For thecompounds known from the literature, the corresponding CAS numbers arealso reported in each case.

a) 6-Bromo-2-fluoro-2′-methoxybiphenyl

200 g (664 mmol) of 1-bromo-3-fluoro-2-iodobenzene, 101 g (664 mmol) of2-methoxyphenylboronic acid and 137.5 g (997 mmol) of sodium tetraborateare dissolved in 1000 ml of THF and 600 ml of water, and degassed. 9.3 g(13.3 mmol) of bis(triphenylphosphine)palladium(II) chloride and 1 g (20mmol) of hydrazinium hydroxide are added. The reaction mixture isstirred under a protective gas atmosphere at 70° C. for 48 h. The cooledsolution is supplemented with toluene, washed repeatedly with water,dried and concentrated. The product is purified via columnchromatography on silica gel with toluene/heptane (1:2). Yield: 155 g(553 mmol), 83% of theory.

The following compound is prepared in an analogous manner:

Reactant 1 Reactant 2 Product Yield a1

92%

b) 6′-Bromo-2′-fluorobiphenyl-2-ol

112 g (418 mmol) of 6-bromo-2-fluoro-2′-methoxybiphenyl are dissolved in2 l of dichloromethane and cooled to 5° C. 41.01 ml (431 mmol) of borontribromide are added dropwise to this solution within 90 min, andstirring of the mixture continues overnight. The mixture is subsequentlyadmixed gradually with water, and the organic phase is washed threetimes with water, dried over Na₂SO₄ and concentrated by rotaryevaporation and purified by chromatography. Yield: 104 g (397 mmol), 98%of theory.

The following compound is prepared in an analogous manner:

Reactant 1 Product Yield b1

92%

c) 1-Bromodibenzofuran

111 g (416 mmol) of 6′-bromo-2′-fluorobiphenyl-2-ol are dissolved in 2 lof DMF (max. 0.003% H₂O) SeccoSolv® and cooled to 5° C. 20 g (449 mmol)of sodium hydride (60% suspension in paraffin oil) are added to thissolution in portions, once the addition has ended the mixture is stirredfor 20 min, and then the mixture is heated to 100° C. for 45 min. Aftercooling, 500 ml of ethanol are added gradually to the mixture, which isconcentrated by rotary evaporation and then purified by chromatography.Yield: 90 g (367 mmol), 88.5% of theory.

The following compound is prepared in an analogous manner:

Reactant 1 Product Yield c1

81%

d) 1-Bromo-8-iododibenzofuran

20 g (80 mmol) of 1-bromodibenzofuran, 2.06 g (40.1 mmol) of iodine,3.13 g (17.8 mmol) of iodic acid, 80 ml of acetic acid and 5 ml ofsulphuric acid and 5 ml of water and 2 ml of chloroform are stirred at65° C. for 3 h. After cooling, the mixture is admixed with water, andthe precipitated solids are filtered off with suction and washed threetimes with water. The residue is recrystallized from toluene and fromdichloromethane/heptane. The yield is 25.6 g (68 mmol), corresponding to85% of theory.

The following compounds are prepared in an analogous manner:

Reactant 1 Product 1 Yield d1

81% d2

67%

e) 3-(9-Bromodibenzofuran-2-yl)-9-phenyl-9H-carbazole

58 g (156 mmol) of 1-bromo-8-iododibenzofuran, 50 g (172 mmol) ofN-phenylcarbazole-3-boronic acid and 36 g (340 mmol) of sodium carbonateare suspended in 1000 ml of ethylene glycol dimethyl ether and 280 ml ofwater. 1.8 g (1.5 mmol) of tetrakis(triphenylphosphine)palladium(0) areadded to this suspension, and the reaction mixture is heated underreflux for 16 h. After cooling, the organic phase is removed, filteredthrough silica gel, washed three times with 200 ml of water and thenconcentrated to dryness. The yield is 48 g (89 mmol), corresponding to64% of theory.

The following compounds are prepared in an analogous manner:

Reactant 1 Reactant 2 Product Yield e1

67% e2

65% e3

62% e4

63% e5

61% e6

60% e7

56% e8

54% e9

68% e10

67% e11

57% e12

60% e13

63% e14

68% e15

63% e16

65% e17

60% e18

58% e19

59% e20

56% e21

52% e22

55% e23

57% e24

56% e25

70% e26

75% e27

72% e28

56% e29

57% e30

62% e31

61% e32

48% e33

46% e34

50% e35

66%

f)3-[1-[9-[(4,6-Diphenyl-1,3,5-triazin-2-yl)-9H-carbazol-3-yl]-8-dibenzofuranyl]-9-phenyl-9H-carbazole

76 g (156 mmol) of 3-(9-bromodibenzofuran-2-yl)-9-phenyl-9H-carbazole,90 g (172 mmol) of9-(4,6-diphenyl-[1,3,5]triazin-2-yl)-3-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-9H-carbazoleand 36 g (340 mmol) of sodium carbonate are suspended in 1000 ml ofethylene glycol dimethyl ether and 280 ml of water. 1.8 g (1.5 mmol) oftetrakis(triphenylphosphine)palladium(0) are added to this suspension,and the reaction mixture is heated under reflux for 16 h. After cooling,the organic phase is removed, filtered through silica gel, washed threetimes with 200 ml of water and then concentrated to dryness. The residueis recrystallized five times from DMF and finally fractionally sublimedtwice (p about 10⁻⁶ mbar, T=350-370° C.). Yield: 81 g (110 mmol), 65% oftheory: 99.9% by HPLC.

The following compounds are prepared in an analogous manner:

Reactant Reactant Product Yield f1

61% f2

53% f3

54% f4

65% f5

67% f6

57% f7

63% f8

63% f9

68% f10

64% f11

66% f12

68% f13

60% f14

58% f15

61% f16

63% f17

63% f18

65% f19

60% f20

58% f21

57% f22

56% f23

51% f24

53% f25

56% f26

56% f27

70% f28

73% f29

72% f30

73% f31

56% f32

55% f33

62% f34

60% f35

45% f36

57% f37

62% f38

65% f39

67% f40

72%

Production of the OLEDs

In examples C1 to I26 which follow (see Tables 1 and 2), the data ofvarious OLEDs are presented.

Pretreatment for Examples C1-I26:

Glass plaques coated with structured ITO (indium tin oxide) of thickness50 nm are treated prior to coating with an oxygen plasma, followed by anargon plasma. These plasma-treated glass plaques form the substrates towhich the OLEDs are applied.

The OLEDs basically have the following layer structure: substrate/holeinjection layer (HIL)/hole transport layer (HTL)/electron blocker layer(EBL)/emission layer (EML)/optional hole blocker layer (HBL)/electrontransport layer (ETL)/optional electron injection layer (EIL) andfinally a cathode. The cathode is formed by an aluminium layer ofthickness 100 nm. The exact structure of the OLEDs can be found inTable 1. The materials used for production of the OLEDs are shown inTable 3.

All materials are applied by thermal vapour deposition in a vacuumchamber. In this case, the emission layer always consists of at leastone matrix material (host material) and an emitting dopant (emitter)which is added to the matrix material(s) in a particular proportion byvolume by co-evaporation. Details given in such a form as IC5:PA1:TEG2(30%:55%:15%) mean here that the material 105 is present in the layer ina proportion by volume of 30%, PA1 in a proportion by volume of 55% andTEG2 in a proportion by volume of 15%. Analogously, the electrontransport layer may also consist of a mixture of two materials.

The OLEDs are characterized in a standard manner. For this purpose, theelectroluminescence spectra, the current efficiency (measured in cd/A)and the external quantum efficiency (EQE, measured in percent) aredetermined as a function of luminance, calculated fromcurrent-voltage-luminance characteristics (IUL characteristics) assumingLambertian emission characteristics. The electroluminescence spectra aredetermined at a luminance of 1000 cd/m², and the CIE 1931 x and y colourcoordinates are calculated therefrom. The parameter U1000 in Table 2refers to the voltage which is required for a luminance of 1000 cd/m².CE1000 denotes the current efficiency which is achieved at 1000 cd/m².Finally, EQE1000 refers to the external quantum efficiency at anoperating luminance of 1000 cd/m².

The data for the various OLEDs are collated in Table 2. Examples C1-C6are comparative examples according to the prior art; examples 11-126show data of OLEDs of the invention.

Some of the examples are elucidated in detail hereinafter, in order toillustrate the advantages of the OLED of the invention.

Use of Compounds of the Invention as Matrix Material in PhosphorescentOLEDs

The materials of the invention, when used as matrix material incombination with an electron-conducting compound (for example compound105 in the examples adduced below) in the emission layer (EML) inphosphorescent OLEDs, result in significant improvements over the priorart, particularly in relation to the external quantum efficiency of theOLEDs. By use of the inventive compounds f40, f, f30, f16 and f21(according to the examples cited above), it is possible to achieve animprovement in the EQE by about 10% to 50% compared to the compoundsfrom the prior art PA1, PA2, PA3, PA4, PA5 and PA6 (comparison ofexamples C1, C2, C3, C4, C5 and C6 with examples I1, I2, I3, I15 andI16).

TABLE 1 Structure of the OLEDs HIL HTL EBL HBL EIL thick- thick- thick-EML thick- ETL thick- Ex. ness ness ness thickness ness thickness nessC1 HATCN SpMA1 SpMA3 IC5:SdT1:TEG2 — ST2:LiQ — 5 nm 230 nm 20 nm(30%:55%:15%) 30 nm (50%:50%) 40 nm C2 HATCN SpMA1 SpMA3 IC5:SdT2:TEG2 —ST2:LiQ — 5 nm 230 nm 20 nm (30%:55%:15%) 30 nm (50%:50%) 40 nm C3 HATCNSpMA1 SpMA3 IC5:SdT3:TEG2 — ST2:LiQ — 5 nm 230 nm 20 nm (30%:55%:15%) 30nm (50%:50%) 40 nm C4 HATCN SpMA1 SpMA3 IC5:SdT4:TEG2 — ST2:LiQ — 5 nm230 nm 20 nm (30%:55%:15%) 30 nm (50%:50%) 40 nm C5 HATCN SpMA1 SpMA3IC5:SdT5:TEG2 — ST2:LiQ — 5 nm 230 nm 20 nm (30%:55%:15%) 30 nm(50%:50%) 40 nm C6 HATCN SpMA1 SpMA3 IC5:SdT6:TEG2 — ST2:LiQ — 5 nm 230nm 20 nm (30%:55%:15%) 30 nm (50%:50%) 40 nm I1 HATCN SpMA1 SpMA3IC5:f40:TEG2 — ST2:LiQ — 5 nm 230 nm 20 nm (30%:55%:15%) 30 nm (50%:50%)40 nm I2 HATCN SpMA1 SpMA3 IC5:f:TEG2 — ST2:LiQ — 5 nm 230 nm 20 nm(30%:55%:15%) 30 nm (50%:50%) 40 nm I3 HATCN SpMA1 SpMA3 IC5:f30:TEG2 —ST2:LiQ — 5 nm 230 nm 20 nm (30%:55%:15%) 30 nm (50%:50%) 40 nm I4 HATCNSpMA1 SpMA3 f1:TER5 — ST2:LiQ — 5 nm 125 nm 10 nm (95%:5%) 40 nm(50%:50%) 35 nm I5 HATCN SpMA1 SpMA3 f2:TER5 — ST2:LiQ — 5 nm 125 nm 10nm (95%:5%) 40 nm (50%:50%) 35 nm I6 HATCN SpMA1 SpMA3 f4:TEG2 — ST2:LiQ— 5 nm 230 nm 20 nm (90%:10%0) 30 nm (50%:50%) 40 nm I7 HATCN SpMA1SpMA3 f5:TER5 — ST2:LiQ — 5 nm 125 nm 10 nm (95%:5%) 40 nm (50%:50%) 35nm I8 HATCN SpMA1 SpMA3 f7:TEG2 — ST2:LiQ — 5 nm 230 nm 20 nm (90%:10%)30 nm (50%:50%) 40 nm I9 HATCN SpMA1 SpMA3 f8:TEG2 — ST2:LiQ — 5 nm 230nm 20 nm (90%:10%) 30 nm (50%:50%) 40 nm I10 HATCN SpMA1 SpMA3 f9:TER5 —ST2:LiQ — 5 nm 125 nm 10 nm (95%:5%) 40 nm (50%:50%) 35 nm I11 HATCNSpMA1 SpMA3 f10:TEG 2 — ST2:LiQ — 5 nm 230 nm 20 nm (90%:10%) 30 nm(50%:50%) 40 nm I12 HATCN SpMA1 SpMA3 f11:TEG2 — ST2:LiQ — 5 nm 230 nm20 nm (90%:10%) 30 nm (50%:50%) 40 nm I13 HATCN SpMA1 SpMA3 f12:TER5 —ST2:LiQ — 5 nm 125 nm 10 nm (95%:5%) 40 nm (50%:50%) 35 nm I14 HATCNSpMA1 SpMA3 f13:TER5 — ST2:LiQ — 5 nm 125 nm 10 nm (95%:5%) 40 nm(50%:50%) 35 nm I15 HATCN SpMA1 SpMA3 IC5:f16:TEG2 — ST2:LiQ — 5 nm 230nm 20 nm (30%:55%:15%) 30 nm (50%:50%) 40 nm I16 HATCN SpMA1 SpMA3f17:TER5 — ST2:LiQ — 5 nm 125 nm 10 nm (95%:5%) 40 nm (50%:50%) 35 nmI17 HATCN SpMA1 SpMA3 f19:TER5 — ST2:LiQ — 5 nm 125 nm 10 nm (95%:5%) 40nm (50%:50%) 35 nm I18 HATCN SpMA1 SpMA3 IC5:f21:TEG2 — ST2:LiQ — 5 nm230 nm 20 nm (30%:55%:15%) 30 nm (50%:50%) 40 nm I19 HATCN SpMA1 SpMA3f24:TER5 — ST2:LiQ — 5 nm 125 nm 10 nm (95%:5%) 40 nm (50%:50%) 35 nmI20 HATCN SpMA1 SpMA3 f25:TEG2 — ST2:LiQ — 5 nm 230 nm 20 nm (90%:10%)30 nm (50%:50%) 40 nm I21 HATCN SpMA1 SpMA3 f26:TEG2 — ST2:LiQ — 5 nm230 nm 20 nm (90%:10%) 30 nm (50%:50%) 40 nm I22 HATCN SpMA1 SpMA3f27:TER5 — ST2:LiQ — 5 nm 125 nm 10 nm (95%:5%) 40 nm (50%:50%) 35 nmI23 HATCN SpMA1 SpMA3 f28:TER5 — ST2:LiQ — 5 nm 125 nm 10 nm (95%:5%) 40nm (50%:50%) 35 nm I24 HATCN SpMA1 SpMA3 f31:TER5 — ST2:LiQ — 5 nm 125nm 10 nm (95%:5%) 40 nm (50%:50%) 35 nm I25 HATCN SpMA1 SpMA3 f33:TER5 —ST2:LiQ — 5 nm 125 nm 10 nm (95%:5%) 40 nm (50%:50%) 35 nm I26 HATCNSpMA1 SpMA3 f39:TER5 — ST2:LiQ — 5 nm 125 nm 10 nm (95%:5%) 40 nm(50%:50%) 35 nm

TABLE 2 Data of the OLEDs U1000 CE 1000 EQE CIE x/y at Ex. (V) (cd/A)1000 1000 cd/m² C1 3.6 44 12.2% 0.34/0.62 C2 3.7 44 12.1% 0.34/0.62 C33.5 45 12.5% 0.34/0.62 C4 3.6 44 12.3% 0.34/0.62 C5 3.5 63 16.9%0.32/0.64 C6 3.6 60 16.7% 0.33/0.63 I1 3.5 68 18.3% 0.34/0.62 I2 3.5 6718.2% 0.33/0.63 I3 3.6 69 18.5% 0.33/0.63 I4 3.6 23 22.4% 0.67/0.33 I53.5 24 22.7% 0.67/0.33 I6 3.5 69 18.5% 0.34/0.63 I7 3.5 23 22.5%0.67/0.33 I8 3.4 66 17.9% 0.32/0.64 I9 3.6 66 18.0% 0.33/0.63 I10 3.3 2522.9% 0.67/0.33 I11 3.6 69 18.7% 0.33/0.63 I12 3.5 68 18.6% 0.32/0.63I13 3.6 24 22.7% 0.67/0.33 I14 3.7 27 23.0% 0.67/0.33 I15 3.6 67 18.4%0.32/0.63 I16 3.5 23 22.5% 0.67/0.33 I17 3.6 22 22.2% 0.67/0.33 I18 3.667 18.2% 0.31/0.64 I19 3.6 27 23.1% 0.67/0.33 I20 3.4 68 18.7% 0.31/0.64I21 3.5 65 18.1% 0.31/0.64 I22 3.3 22 21.9% 0.67/0.33 I23 3.4 23 22.5%0.67/0.33 I24 3.5 23 22.4% 0.67/0.33 I25 3.4 24 22.8% 0.67/0.33 I26 3.528 23.1% 0.67/0.33

TABLE 3 Structural formulae of the materials for the OLEDs

1.-15. (canceled)
 16. An electronic device comprising at least onecompound according to formula (1)

where A is CR; Y is O or S; W is the same or different at each instanceand is CR or N, where not more than one W group per cycle is N and whereW is C when an L¹ or L² group is bonded to this position, or twoadjacent W groups together are a group of the following formula (2) or(3), where each of the two carbazolyl derivative groups in the compoundof the formula (1) have not more than two groups of the formula (2) orformula (3):

where the dotted bonds indicate the linkage of this group, A hasdefinitions given above and Z is NR, CR₂, O or S; Ar¹, Ar² is anaromatic ring system having 5 to 30 aromatic ring atoms or adibenzofuran or dibenzothiophene group, where the aromatic ring systemor the dibenzofuran or dibenzothiophene group may be substituted in eachcase by one or more nonaromatic R radicals, or is a group of one of thefollowing formulae (4) and (5):

where the dotted bond represents the bond to the nitrogen atom; with theproviso that exactly one of the Ar¹ and Ar² groups is a group of one ofthe formulae (4) and (5); X is the same or different at each instanceand is CR or N, where X in formula (5) is C when the group of theformula (5) in this position is joined to L³, with the proviso that, informula (4), two or three X groups are N and, in formula (5), one, twoor three X groups are N; L¹, L², L³ is the same or different at eachinstance and is a single bond or an aromatic or heteroaromatic ringsystem which has 5 to 30 aromatic ring atoms and may be substituted byone or more R radicals; R is the same or different at each instance andis selected from the group consisting of H, D, F, CN, N(R¹)₂, C(═O)R¹,P(═O)(R¹)₂, Si(R¹)₃, a straight-chain alkyl or alkoxy group having 1 to20 carbon atoms or a branched or cyclic alkyl, or alkoxy group having 3to 20 carbon atoms, each of which may be substituted by one or more R¹radicals, where one or more nonadjacent CH₂ groups may be replaced by 0,and where one or more hydrogen atoms may be replaced by D or an aromaticor heteroaromatic ring system which has 5 to 40 aromatic ring atoms andmay be substituted in each case by one or more R¹ radicals; at the sametime, it is optionally possible for two R substituents bonded to thesame carbon atom or to adjacent carbon atoms to form a monocyclic orpolycyclic, aliphatic, aromatic or heteroaromatic ring system which maybe substituted by one or more R¹ radicals; R¹ is the same or differentat each instance and is selected from the group consisting of H, D, F,CN, N(R²)₂, a straight-chain alkyl group having 1 to 10 carbon atoms ora branched or cyclic alkyl group having 3 to 10 carbon atoms, each ofwhich may be substituted by one or more R² radicals, where one or morehydrogen atoms may be replaced by D or F, or an aromatic orheteroaromatic ring system which has 5 to 40 aromatic ring atoms and maybe substituted in each case by one or more R² radicals; at the sametime, it is optionally possible for two R¹ substituents bonded to thesame carbon atom or to adjacent carbon atoms to form a monocyclic orpolycyclic, aliphatic, aromatic or heteroaromatic ring system which maybe substituted by one or more R² radicals; R² is the same or differentat each instance and is selected from the group consisting of H, D, F,CN, an aliphatic hydrocarbyl radical having 1 to 20 carbon atoms, or anaromatic or heteroaromatic ring system having 5 to 30 aromatic ringatoms in which one or more hydrogen atoms may be replaced by D, F, CNand which may be substituted by one or more alkyl groups each having 1to 4 carbon atoms; at the same time, it is possible for two or moreadjacent R² substituents together to form a mono- or polycyclic,aliphatic ring system.
 17. The electronic device according to claim 16,wherein the electronic device is an organic electroluminescent deviceand the least one compound according to formula (1) is used as matrixmaterial for fluorescent or phosphorescent emitters in an emitting layerand/or as electron transport or hole blocker material in an electrontransport layer and/or in a hole-blocking layer.
 18. The electronicdevice according to claim 16, wherein the least one compound is selectedfrom the compounds of the formulae (7a), (7b), (7c), (7d) and (7e)

where: W two adjacent W groups together are a group of the followingformula (2a) or (3a) and the two other W groups are CR, where W informula (7d) is C when an L¹ group is bonded to this position, and informula (7e) is C when the dibenzofuran or dibenzothiophene is bonded tothis position:

where the dotted bonds indicate the linkage of this group; n is the sameor different at each instance and is 0, 1, 2, 3 or 4; m is the same ordifferent at each instance and is 0, 1, 2 or 3; the further symbols usedhave the definitions given in claim
 16. 19. The electronic deviceaccording to claim 16, wherein L¹ and L² are single bonds.
 20. Theelectronic device according to claim 16, wherein the at least onecompound is selected from the compounds of the formulae (9a), (9b),(9c), (9d) and (9e)

where W, n and m have the definitions given in claim 17 and the furthersymbols used those given in claim
 16. 21. The electronic deviceaccording to claim 16, wherein in the at least one compound the group ofthe formula (4) is selected from the structures of the formulae (4-1) to(4-3) and that the group of the formula (5) is selected from thestructures of the formulae (5-1) to (5-18)

where the dotted bond represents the bond to the nitrogen atom and inaddition: R is the same or different at each instance and is H, an alkylgroup which has 1 to 10 carbon atoms and may be substituted by one ormore R¹ groups, or an aromatic or heteroaromatic ring system which has 5to 40 aromatic ring atoms and may be substituted in each case by one ormore R¹ radicals.
 22. The electronic device according to claim 16,wherein in the at least one compound L³ is a single bond or an aromaticring system having 6 to 12 aromatic ring atoms.
 23. The electronicdevice according to claim 16, wherein in the at least one compound theAr¹ or Ar² group which is not a group of the formula (4) or (5) isselected from the group consisting of phenyl, ortho-, meta- orpara-biphenyl, terphenyl, quaterphenyl, 1-, 2-, 3- or 4-fluorenyl, 1-,2-, 3- or 4-spirobifluorenyl, 1-, 2-, 3- or 4-dibenzofuranyl and 1-, 2-,3- or 4-dibenzothienyl, each of which may be substituted by one or morenonaromatic R radicals.
 24. The electronic device according to claim 18,wherein in the at least one compound the index n is the same ordifferent at each instance and is 0, 1, 2 or 3, and in that the index mis the same or different at each instance and is 0, 1 or
 2. 25. Theelectronic device according to claim 16, wherein in the at least onecompound R is selected from the group consisting of H, D, F, CN, N(R¹)₂,C(═O)R¹, P(═O)(R¹)₂, a straight-chain alkyl or alkoxy group having 1 to10 carbon atoms or a branched or cyclic alkyl or alkoxy group having 3to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, eachof which may be substituted by one or more R¹ radicals, where one ormore nonadjacent CH₂ groups may be replaced by O and where one or morehydrogen atoms may be replaced by D or F, an aromatic or heteroaromaticring system which has 5 to 24 aromatic ring atoms and may be substitutedin each case by one or more R¹ radicals; at the same time, it isoptionally possible for two R substituents bonded to the same carbonatom or to adjacent carbon atoms to form a monocyclic or polycyclic,aliphatic, aromatic or heteroaromatic ring system which may besubstituted by one or more R¹ radicals.
 26. The electronic deviceaccording to claim 16, wherein the least one compound is selected fromthe compounds of the formulae (10) and (11)

where the symbols used have the definitions given in claim 16 and Ar isthe same or different at each instance and is an aromatic orheteroaromatic ring system which has 5 to 40 aromatic ring atoms and maybe substituted by one or more R¹ radicals.